Synchronous signaling system



March 8, 1932.` w. A. KNooP SYNCHRONOUS SIGNALING SYSTEM Filed May 2l. 1930 /NvE/vof? W. A. KNOOP By .Y 2Q vRm.

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"NQRY s ArToR/VEK Patented Mar. s, 1932 l UNITED* STATES. PTgLENT '01eriCe*wf 'WILLIAM In. imoor,y or nmrsrnnn, Yonzmfnssrenon To anni Tanninonn LABORATORIES, :meenten-Armi, YORK Application filed vKay 21,

' Tliisinvention relates to a synchronous communication 'system and particularly toa cuit for yinserting in the train of received impulses unit length impulses of alternately opf postte polar ities ycorresponding to those which are lost in transmission.' VBy uslngthe 'interpolating circuit,rytheispeed of signaling is'increased to a point Where only the positive-and Y negative impulses of two or more units length are., after being amplified-capable oi operating or controlling the receiving apparatus.

the traffic capacity of the cable 'is increased. `According to thie present invention the principle of the interpolating system is applied to ycarrier currenty telegraphy over-a loaded Vsubmarine cable or any similar type kof carrier Wherebythe traiic capacity of each carrier channel is increased. lt is generally known. 'that in systems wherein multiplex telegraph apparatus isoperated over carrier circuit-s, the Width of the signal frequency band plays an important part in determining the number of carrier channels that can be profitably used on a cable or line, so if itis desired lto increase t ie traliic over a given cliannelit'is necessary to make the frequency band convey vmore intelligence than it would ordinarily. This is accomplished inthe present invention by utilizing eachicarrier channel fortransmitting signals from tivo or more multiplex` lines.

For illustration the invention is described herein asoperating iny asystem designed to receive signals from tivo four-channel multiplex lines the printingequipment, to a submarine cable employ- By thus increasing the speed of transmission,

pulses Y are divided into `tvvo groups operated at the normal speed of ss'mcnnonecs meneame 'srsfrfeiu 1930; 'seriali auftragen-.if f y n p operated at high speed over acarrer current channel.' The carrier cirouitgis suchl that it vill ordinarily permit the transmission of` v signals frolnonly' onefour-.channel line but byarranging the circuit to' rejectone :halfthe lengthI ot each of the inifpulses'received from the two lines, the Aother lialves ofthe-.impulses received inlay `be combined v for further trans mission. Thus'the signals ofeightchannels are obtained for transmission? overA a carrier 'channel ordinarily designed to operatev at a speedk of four-channel transmission. f vThe Lcombined implses'- are repeated through a Vnetwork wherein the vim ulses 'of half unit l length andfof alternate yopposite polari- 'ties7 or other words,:tl1e higher ,frequency reversals, are suppressed.-v The impulsesgof two or more halfunits'len'gtho the one p0- larity Whichpass through r'th'lnetwork, apply potemsialsk in seriesA with'the potentials from a carrier current source to the gridcircuitrof a vacuum' tube wherein-modulation Y takes place.v The modulated current is'tr'ansnitted' over thecarrier*-v channel tothe receiving station Whereit is .demodulated;' lThe signaling current after demodulation is impressed ona regenerating-and interpolating ,circuit ywherein. the signalingl vcurrentl im-` Y and theA impulses :constituting k.the Vhigher frequency orv New YORK, n. vga, concentran or NEW reversals are furnished toy the'two Vgroups to *Y replace those that were suppressed. The two groups of signals are then directed over two four-channel Vmultiplex lines In this' way twicey as many signal impulses fromA multiplex telegraph lines may be fsimultaneo'us'y repeated overi'a single carrier :channel to other multiplex` telegraph lines as would Mordinarily be vppssible.' u e n This may e done conveniently by providing two multiplex lines eedingfinto tliecarrier systembut may be accomplished byfusing any desired number operating at suitable In g'emral, the application of they foregoing* s principles enables the tracl capacity of any carrier telegraph circuit?,y of .which the tratley capacity islimited by thevband .jwidth, to be doubled-YV -f i Y ABy providing additional sources, ofcarri-er current of widely diierent frequencies at the repeater station, additional carrier channels are provided whereby other groups of multiplex lines may be connected for simultaneous operation over the one cable. In systems of this type, the carrier frequencies used for transmitting in one direction are all included within one range of frequencies and all the carrier frequencies used for transmitting in the oppositey direction are ineludedwithin mother range of frequencies.

A more detailed description of one speciesv of the invention 1s given 1n conJunction with the single figure shown in thedrawing.- v

Referring to the drawing, two terminall stations X and Y each equipped with mult-iplex (four channel) equipment, are shown connected to a repeater station Z over conductors ,1l-12 and 13-14, respectively. Conductors 11 and 13l are paths over which signals are transmitted to the repeater station Z from sending equipments 15 and 16,

respectively, and conductors 12 and 14 are paths overwhich signals received by station Z from the cable, are repeated to the receiving equipments 17 and 18, respectively, thereceived signals being also effective to operate the corrector equipments 19 and 20, respectively provided at the terminal stations X and Y. The sending, the receiving and corrector -equipment-s are shown diagrammatically butk are understood to comprise yfour channel rotary Adistributors arranged to be driven in synchronism. These equipment-s are well known in the art and require no f urther description.V -f

vThe signals aie transmitted over conductors 11 and 13 simultaneously and are effective to operate twounbiased Apolarized sending-on relays 21 and 22.; The relay armatures kreproduce the incoming signals yfor transmission over the contact bars of a kcontinuously rotating commutator 23, having engagement with the contact bars, three stationary brushes 24, 25y and 26, the direction of rotationy ofthe cominutator being indicated by an arrow on the drawing. The signals reproduced by relay 2l are impressed on the comniutator over brush 24 and those reproduced by relay 22 and impressed over brush 25. The commutator is provided with forty contact bars of equal width` twenty of sections because they are capable of transmitting signal impulses. The short sections,

serving merely as spacers or buffers, are referred to as dead sections. The live sections ot adjacent bars are iii staggered relation with respect to cach other as are also the dead sections. In other words, each of the brushes 24 and 25 which engage thc end lportiolnsof the bai's, 'passes over alternate live and dead sections, and brush 26 which engages. thel middle portions of t-lie bars, passes over thelong sections only. Brushes and 25 arc positioned the width of one bar or more .in advance of brush 26.' In this way brushes 24. and 25 engage each bar before brush 26. Brushes and 25 are arranged tobe in engagement with the long sections Vduring the arrival of the center lportions of the impulses which are to be stored:` yThese brushes are independently orientable so thatr Aadjustment of any one brush may be made without interfering with either of the othern 85 brushes.

The long sections on each side of the comvmutator are interconnected to form five groups or multiples of four each, to correspond to the five pulse code employed in. themm) four transmitters at each of stations X and rY. The five multiples engaged by brush 24 are arranged to receive signalimpulses from transmitters A, B, C and D, respectively, at

station X, and the five multiples engaged bye brush 25 are arranged to receive signal im- -pulses from transmitters E, F, G and H,

respectively, at station Y. the transmitters notbeing shown but understood to be ineluded yin the blocks 15 and y16. The five im-z pulses from each transmitter are received successively, the impulses from the transmitters in block 15 being received with those t from the transmitters in block 16. The five multiplesv on one side of the commutator aren successively engaged in continuous rotation brush 24 and the five multiples on the other side are similarly engaged by brush 25. The -five kmultiples engaged by brush 24 are connected to ground 27 through storing con-.1, -densers 28y to 32, respectively. and the five multiples engaged bvibrush 25 are connected to ground 33 through storing condensers 34 to38, respectively. It will be noted that only the long, or live, sections of the commutator-` bars are arranged to receive the transmitted impulses Whereas the short sections are left dead and merel)v serve as buffer segments. The phase relations betweenr stations X and densers hold the impulses until required and the combining connnutator 23 releases the stored impulses. t

By having brushes 24 and 25 positioned in advance of brush 26 the impulses produced by relay 21 cause each of condensers'28 to 32 in turn to be charged with its incoming ini- 4pulses in rotation.l The impulses reproduced by `'relay 22 cause each of eondensers 34 to 38 Y are immaterial because the storing con-- in turn to be also charged-in rotation. It will 13 Lam-isi' be med that @seh ofliirushes f2s :m 25 en-- alternate iive' and den@ 'eert-'ions` In this :my only the" eeiiter portionsof impulses transmitter at stutien .is rnnrerlateiy foif Ioweelr by :s eorrespendingv impni'se kfrom n transmitter srt-station 'for transmission over Y the linen; Inv this wey tir-ef imperiales of the trmfsniittersnt station X irre-interleerecl respectively with impulses from thevr transmit, `ters at station Y. Theinterlenvec. Iimpsnses in the output of veenum tube transmitter 93'9- ere iin-pressed` onnetwerk- 40` wiie'fe-n any sonaretoppedfA portions are 'rounded to pioacir a eine Waveoiin anfistii'e impulses of? irzrlf unit lengtlr and of 'fflteratefoposite polarity a'r-esuppresseclin oreferto clieeresrse the Wi-clth of. tiie iizmfof transmitter? Yire'- qneneies. By e 'unit length i-ninrise, :fs used hereinafter is meente half impulse Wliiclifis 'stored on a eondenser connecten4 tothe conimota-ton The signal crrrrent were Wiiieli passes tlirouglr network 4?- is imprese-.eil on 1 of tiie'rnofinllzrtor tribe .42 togiier Wit-ii 'ea-rrifervotirge obtaned'froni the secorifary wirieling of 'transformer' {r1/f. tlife` primary Winding ofwhieifi is connected? to :1 sonrt'e ofearrier current. The combine@ witziges l impressa? en the Vvz'reunrn tube rnoelnmtor eunsesf the* variations-ofthe signal were to iin-pressed onl the carrier were 'EF1-e moctnitet wave isparsserl throwgnbsnci pes; filter 45,: a transmitting nrnpliier :rmi a owqoess eiireetiorr filter i511 in series, to the Linel or cable VThe benclfpzrss iter is vclesiggirieet pass only onefsiele borrel of tire carrier freqneneypreetneed at sorrrceto @other with the eaalri'fer eqfnetey. In zt sys.

` teni 'of-this typegrzs state@ ritme, the sorrisi' frequencies: used: 'for trsmemittmgf in one gir re @tionv indent-eri within one framge of.

qi'leneiess and fill the @terrier yireffuerwiesy used for transmitting in the oppositeetfreeten are i inehtcled withinnfnot frange of frequencies. "Eireieiore to 'meetthis condition the carrier ernment alt: station Z is' or kmfrumeney 'with respect tothfat or" iated' ai repeater' station @ttl-ie opposite en et line Yor 46, the Vclirection fitter' is--oi the lowpess so to prevent tire irigi" er zeefuennies' ineoriring' from 'the @wie from eirr` tering' the transmitting' equipment :1t stafti'on Zi.. f f

Tire equipment at the" repeaterzmti tei-mi nali mt the opposite endoftifo tem (inet slfiowiu are afssu'm" `VI. to be t l tli'ose shown in? fined ling"exf e'iptt` :it the' elistmitrepewterstotion'the nrw-oi' ein :re/if corren-it isfo a hivtgn-ireqmieney anni: the dii i'eetion'filter employed in tlietrsusnntting circuit is of the high-pass type; Therefore 'the receiving equipment :it repeater :station Z' nnd'terininzil stations X and Yjwill be used 1n deseribi-ng'tiie operation of the receiving equipment at thev ciistant end oi' the cableain response to signals trunsnii-ttmlfroni station' Y except that the incoming carrier enrre'n't will be assumed to be 'oi a high iref queries'.

n bin-icl pass' filter 49 which is selecteil of the partienlirr eine Emmiy of frequencies effective to' pzisstlie l-Ja'ndpess lterin the transmitting n eifrenit it tlie repeater station the Vvopposite enel of the cable. Bancipass filter {if}Y is adapt-j,

edf, Yof Coni'se,'t'o pass si' range oi higher freqcieneiesthan band pnssiier .133 because oiv the assumption that the incomingwares gire eir'rploying" oarrie'r current ofthe higher fref qnerr'cy, Tlie"rnoclulzitejwnve is,` theirinir Y pressefl on the clelnoflulator 50 Whe-rein lie l l'o-W yfiequenoy modulating Vor signal Wave reproduce@ Wit-hout the oni-rief current Wzive :trici clireofe toftlife receiving'riiigs of e multi'- pleX rotary distributor. Tliiswave now' closely resembles that produce-cl by circuit 40 inst prior to' modulation; all the 'nnit'iinpulses' 'snial'lg Ain amplitnde'nnd are incapable Con'- trolling the receiving equipment. The irnpulses consisting of `two or more pulses'. of

tary clistriibut'or` is inainteinerlin synchrono'ns phase. with' the incoming' signfils by n.

continuons electrical` corrector Vcircuit shown diagrninmatiezilly in' block' and" disci'osec in Various' forms' in the applicants @opendi-ng application Serial No. elfiled April 'terpol'ating' circuit are di'selosecl and deseribeel' in applicantscontending application TST. T929', Wlierein detailed description may sei-iai Nerf-s228231, fire-d Marchi. 15e-3o. l This equipment comprises the receiving'rinnjs of 'the multiplex rotary distributor, Whiclra're adapterl to receive signals over eight chair-V nel-'s to correspond to the four-`channel dis'- trilinitors at the4 terminal sstionsf The rings rare' arranged afsfsliown in Fig. l of the Clrrwf ings of the copendino"application Serial No;

432,288', supra, but there' `eli-ey are shownyas being adapted for six channels, whereas in the present invention they are provided for eight channels. However, 'the arrangements i in the copeiiding application may be adaptf ed for any even number ot channels wherein latter ring being divided into eighty alternate long and short segments of twenty segments for each pair ot channel The long segments are connected in multiple to the output circuit of demodulator and the short ksegments are connected in multiple to torni two groups, the segments ot one group being .interleaved with the segments of the other group.V rlhe two groups oi short` segments are respectively connected to tivo vacuum tube storing circuits; Connected to the continuous ring is a storing condenser Which is arranged to receive the incoming signal impulses from the output circuit ot thev demodulator as the distributor brush rotates over the long segments and to transmit the stored charges to either of the vacuum tube circuit-s as the brush subsequently rotates over the short segments. The two groups of short segments are arranged to respectively receive in succession the impulses which were received at the repeater station at the jdistant end of the line from the two terminal stations directly connected thereto. Thus the impulses transmitted from one terminal station are received by one vacuum tube circuit and those transmitted from the other tei'- minal station are received by the other vacu-` um tube circuit.

The vacuum tube storing' circuits each coin- 'J prise a pair ot' vacuum tubes connected in cascade and with their plate circuits con nected to a common battery. Connected in shunt to the plate circuits of each of the vacuum tubes is a receiving relay and any difterence in potential occurring between the vpoints ot' the circuit to which each relay is connected, will operate the relay. The normal plate currents of the vacuum tubes ofl each pair are balanced and therefore the relays which are of the unbiased polarized ,type will normally maintainy their respective armatures in engagement with one of their associated contacts. The contacts ot each relay are connected to opposite poles oit the grounded hat tei-y. The armature of one receiving relay is connected in the circuit extending through the windings of a printer relay 53, through a regenerating resistance 54 to ground and the armature ot the other receiving relay is connected in a circuit through windings ot printer relay 55, regenerating resistance :TG to ground. T he printer relays 53 and 55 and regenerating resi stances 54 and 56 are shown in the drawing of the present application. Relays 53 and 55 are also of the unbiased polar.-

ized type and normally assume positions corresponding to those of the receiving relays respectively. Contacts of relays 53y andl 55 are connected to opposite poles of battery 57. The armatures of relays 53 and 57 vare respectively connected to Amonitoring circuits 58 and 59 which maybe similar to the printer circuits shown in Fig. lof the, copending application Serial No. 432,288, supra.

. To interpolate impulses at stat-ion Z in order to replace those of unit le h (half lengt-h) which were suppressed at t ie distant end of the cable, current-s of alternate positive and negative `polarities are generated from the localisource of potential 57 as the brushes rotate over the receiving or monitoring ring sets, provided, of course, that4 no signaling impu ses oftwo or more units length are received inthe interim from the deinodulator y50. The interpolating of the unit vim )ulses of alternately positive and negative po arity which are produced by printer relays 53 and which normally maintain their respective armatures inopposite positions, is described in detail in copending application Serial No. 432,288, supra.

The armatures of relays and 55 are respectively connected overzlines 12 and 14 to the 'receiving circuits at stations X and Y. Linesl 12jand 14 are connected kat stations X and Y respectively to the windings of relaysmf() and A61, in series, Vand to the windings ot relays r62 .and 63, in series. Relays 60 to G3 inclusiveai'e of the biased polarized type. Relays and .61 reproduce the impulses received over line 12 to operate the receiving equipment 17 `and the corrector equipment 19 at station X and relays 62 and 63 reproduce the impulses received overline 14 to operate receiving equipment 18 and corrector equipment 20 at station Y. The ,receiving distributor rings at stations X and Y may be similar to the printer distributori-ings shownin Fig. 1 of the drawings 'in the c0- pending application, Serial No.` 432,288, supra, and therefore, inasmuch as the printer relays 58 and 54 are alternately operatedfor energized, their armatures will remain in either position sufliciently long to operate the slow acting Aprinter. magnets. In this way the impulses as originally transmitted, but changed to half unit length by the cominutator, are restored to their oi'iginal'length.

The above description treats of a system having one carrier channel but it is understood that the present invention may be applied to a'system having several such channels. In the drawing is shown Aindot and dash lines av block 75 which represents diagrammatically a second coininutator circuit connected to another pair of terminal stations X2 and Y2. This circuit comprises sendingon relays, a coininutator and its associated brushes, a vacuum tube transmitter, suppressing network, a source of carrier current of les iso

, maaier a a .diitereiat frequency from .that otsource 42,- butivithin the lower range-"so, assto pass` loan-passV direction tilt-erde, amodulator and Y aband passv lilterdesigned ,tozp'asswone of thesidebands vof thefrequencyof theffcarrier source .connected to it.. This yblock 75 is shown connected to transmitting.amplifier all.r In .order to complete the tWo-ivay transmission, a second-source of carrier current isl employed at the distant repeateistation :but f inthe vrange ot higher frequencies andthe:

modulated signal Wave 1 incoming over* cable 4:6 .at'station Zi will. be received in .a secondY receiving circuit shown diagrammatically by" bloeli-y '76' and transmitted overvlinesto the second lpair of terminal-stati ons -X2 and Y lYliat'is claimed is:`

with means at the receiving end off-the car7 rier system comprising aHf-listributor synv chrnnized with the .distributor'systein at the transmitting end kof the carrierchannel for interpolating impulses necessaryfor the receptionof the transmitted-.intelligence and of a smaller time duration than thosederived iii `eiective amplitude from the modulated carf f rthose that are lost by. attenuation and for rierwave. .y t Y o 'Qnlna system for increasing thepmessage capacity of a carrier Wave channel employi ingcmndulated Waves Without increasing the frequency of recurrencevot the modulating impulses, which comprises means for producing single unit impulses rand impulses which vare a multiple of the length thereof, means for suppressing the single unitfinipulses,

means yior modulating a carrier wave by the n remaining impulses, a .demodulator for the carrier Wave, and means controlled by the products of demodulation for regenerating the unit impulses in their proper relationship to the multiple unit impulses.

Y 3. `Asystem for the transmission of intelligence comprising a carrier system, a carrier current channel, a plurality of multiplex systems connected to eachend of said channel,

a distributor system'for supplying from `the plurality of multiplex systems at the ytransmittingrend to the carrier Wave impulses representing intelligence to be-transmitted, in

` combinationwith means at the receiving end of the carrier system comprising a distributor synchronized With ythe distributor system i at the transmitting end of the. carrier channel, for interpolating impulses necessary/,tor

the reception of the transmitted intelligence and of a smaller time duration than those derived in effective amplitude from the modulated carrier Wave.

. e. In an impulse transmission system, a plurality of multiplex transmitting circuits',

a plurality of multiplex receiving circuits, a

circuit for interconnecting said transmitting and` receiviiig-circuits, characterized in this', that a portion, with respect to time, of an impulse received tromone of said transmit ting circuits is Acombined with a portion ot an impulse receivedtrom they othery of said transinitting circuits Ltoviioim other impulses for transmission over said interconnecting circuit to said receiving circuits,

5,7111V an impulse transmission system `in accordance Wit-li claim 4 further characterv izedin that means are employed intermediate f said .transmitting circuits and said intercomV means Aare provided for interpolating single, unit impulsesiot alternately opposite polari-r ties inthe incoming impulse ivave to replace separating the received and interpolated impulses into groups tor transmission. over their respective lines of the other of said' groupsof lines extending to said terminating station. f

7k. ln a communication system, groups of multiplex signalinglines, a carriercurrent channel interconnecting said groups of lines, characterized in this that portions, Withre speet to time, of the signal impulses received from thelines of one of said line groups are combined in successive ordei' and impressed on a circuit wherein the single unit impulses ot valternately opposite polarities are sup, pressed and. the ysuccessive unit impulses of ,ica-

onepolarity are permitted to be transmitted Y over said channel,A singleunit impulses oi alternatel fi jopp'osite polaritiesV being i intere polatedatthe terminatingend of said channel ,Wlierethe signal and interpolated im- .Y

pulses are separated into groups tor trans missionA over ot said .groups otlinesik a f v dirija' communication system, groups ofv multiplex `signaling lines, a .carriery current ot one of said groups, means t'oi storing portions, with respect-.to time, of each of .said

impulses, means for combining` in a successive order the stored portions ot the impulsesI portions to forma Wave of high signaling the respective lines of the: other 'channelinterconnecting saidgroups, meansr torreceiving signal impulses from the-lines I frequency, means for suppressing in said wave the unit length impulses of alternately opposite polarity, means for modulating the carrier current over said channel with the signal wave constituted of impulses of only two or more units length, and means at the terminating end of said channel for interpolating the suppressed impulses and direct ing both the interpolated and received impulses to the lines of the other of said groups.

9. In a signaling system, a group 'of low speed ltransmission lilies, a second group of low speed transmission lines, a carrier currentchannel capable of transmitting high frequencies interconnecting said groups of lines, multiplex equipment arranged to transmit signals of positive and negative polarity over each oi said low speed lines of the first mentioned group, means for combining in a successive order the signal impulses respectively received over the lines of said first mentioned groups, means for suppressing the unit y length impulses of alternately opposite pola'rities in the combined impulse wave, means employing carrier current for transmitting combined impulses of only tivo or more units length of one polarity over said channel, and means at thc receiving end ofthe channel for separating the signals from said carrier current, interpolatingI current impulses of unit length corresponding to the unit length impulses suppressed before transmission 'over the channel and directing the signals as originally transmitted over each line of the first mentioned group to a line of the second mentioned group. f

l0. In a signaling system in accordance with claim 6 wherein the means for combinin g signal :impulses comprises a rotating commutator, a plurality of Contact brushes for receiving impulses in random phase from the lines of one of said groups and impressing them on diiiferen't sections of the commutator, groups of storing elements respectively provided for the lines of one of said groups, the storinffelements in cach group being respec tively arranged to stor-e a portion, with respect to time, of each of thel impulses received, and another contact brush for'ctfecting the connection of said storing elements in succession for transmission of their respective charges over the carrier channel.

ll. In a. signaling system, groups of low speed transmission lines', other groupsof low speed transmission lines, a transmission circuit for interconnecting said groups, a pluralityof sources ot carrier current capable of transmitting currents of Widelydifferent frequencies, multiplex equipment arranged for transmitting signals ot positive and negative polarity over each ot said low speed lines. means forcombining in a successive order the signal impulses respectively received from the lines of each group, means for suppressing the unit length impulses of alternately opposite polarity, means employing the carrier currents from said plurality of sources for simultaneously transmitting over said interconnecting ycircuit adjacent unit length impulses `oflike polarity respectively' received from lines of each of the first mentioned groups, and means at the receiving end of said interconnecting circuit for separatingthe carrier currents into separate channels, subsequently separating the signal impulses from their respective carrier currents, then simultaneously dividing into separate groups the interleaved signal impulses received from ythe lines of each of the first mentioned groups and interpolating in each of said yseparate groups impulses of unit length and of alternately opposite polarities corresponding to the unit length impulses suppressed before transmission over its respective channel, and directingthe signals as originally transmitted over cach of the lines of each of the first mentioned groups to its corresponding line of each of the second mentioned groups.

12. In asignaling system in accordance with claim 1l wherein the means for dividing the interleaved impulses of each incomin g signal wave into separate groups and interpolating the unit length impulses of alternately opposite polarities in said groupsk comprises a rotary distributing device.

In witness whereof, I hereunto subscribe my name this th day of May, 1930.

WILLIAM A. KNOOP.

lUi 

